Telephone line measuring and test equipment employed by telephone service providers customarily employs a variety of conditioning and signal generation components in order to enable service and maintenance personnel to apply a prescribed number of electrical stimuli to the line, for the purpose of trouble-shooting the line and measuring its performance. Among these various components are tone generation circuits and electrical conditioning sources that are used to selectively transmit prescribed test signals to the line (such as DTMF tones, a 577.5 Hz tracer tone, a 30 Hz line capacitance measurement sine wave) and to condition the line with a set of electrical circuit parameters (e.g., predetermined D.C. voltage levels) that allow a line monitoring unit to conduct line resistance and capacitance measurements and thereby determine the current state of the line and its ability to successfully perform as intended.
In the past, such stimuli have conventionally been sourced from multiple single-function circuits, which are selectively switched into or applied to the telephone line upon which measurements are to be conducted or for which throughput and performance are to be verified. Because the number and variety of measurements for which the test circuitry must be equipped is not insubstantial, the number of conditioning and signal source components that must be contained within the test circuitry results in a device that is both complex and costly.